| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame] | 1 | C2 port support |
| 2 | --------------- |
| 3 | |
| 4 | (C) Copyright 2007 Rodolfo Giometti <giometti@enneenne.com> |
| 5 | |
| 6 | This program is free software; you can redistribute it and/or modify |
| 7 | it under the terms of the GNU General Public License as published by |
| 8 | the Free Software Foundation; either version 2 of the License, or |
| 9 | (at your option) any later version. |
| 10 | |
| 11 | This program is distributed in the hope that it will be useful, |
| 12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | GNU General Public License for more details. |
| 15 | |
| 16 | |
| 17 | |
| 18 | Overview |
| 19 | -------- |
| 20 | |
| 21 | This driver implements the support for Linux of Silicon Labs (Silabs) |
| 22 | C2 Interface used for in-system programming of micro controllers. |
| 23 | |
| 24 | By using this driver you can reprogram the in-system flash without EC2 |
| 25 | or EC3 debug adapter. This solution is also useful in those systems |
| 26 | where the micro controller is connected via special GPIOs pins. |
| 27 | |
| 28 | References |
| 29 | ---------- |
| 30 | |
| 31 | The C2 Interface main references are at (http://www.silabs.com) |
| 32 | Silicon Laboratories site], see: |
| 33 | |
| 34 | - AN127: FLASH Programming via the C2 Interface at |
| 35 | http://www.silabs.com/Support Documents/TechnicalDocs/an127.pdf |
| 36 | |
| 37 | - C2 Specification at |
| 38 | http://www.silabs.com/pages/DownloadDoc.aspx?FILEURL=Support%20Documents/TechnicalDocs/an127.pdf&src=SearchResults |
| 39 | |
| 40 | however it implements a two wire serial communication protocol (bit |
| 41 | banging) designed to enable in-system programming, debugging, and |
| 42 | boundary-scan testing on low pin-count Silicon Labs devices. Currently |
| 43 | this code supports only flash programming but extensions are easy to |
| 44 | add. |
| 45 | |
| 46 | Using the driver |
| 47 | ---------------- |
| 48 | |
| 49 | Once the driver is loaded you can use sysfs support to get C2port's |
| 50 | info or read/write in-system flash. |
| 51 | |
| 52 | # ls /sys/class/c2port/c2port0/ |
| 53 | access flash_block_size flash_erase rev_id |
| 54 | dev_id flash_blocks_num flash_size subsystem/ |
| 55 | flash_access flash_data reset uevent |
| 56 | |
| 57 | Initially the C2port access is disabled since you hardware may have |
| 58 | such lines multiplexed with other devices so, to get access to the |
| 59 | C2port, you need the command: |
| 60 | |
| 61 | # echo 1 > /sys/class/c2port/c2port0/access |
| 62 | |
| 63 | after that you should read the device ID and revision ID of the |
| 64 | connected micro controller: |
| 65 | |
| 66 | # cat /sys/class/c2port/c2port0/dev_id |
| 67 | 8 |
| 68 | # cat /sys/class/c2port/c2port0/rev_id |
| 69 | 1 |
| 70 | |
| 71 | However, for security reasons, the in-system flash access in not |
| 72 | enabled yet, to do so you need the command: |
| 73 | |
| 74 | # echo 1 > /sys/class/c2port/c2port0/flash_access |
| 75 | |
| 76 | After that you can read the whole flash: |
| 77 | |
| 78 | # cat /sys/class/c2port/c2port0/flash_data > image |
| 79 | |
| 80 | erase it: |
| 81 | |
| 82 | # echo 1 > /sys/class/c2port/c2port0/flash_erase |
| 83 | |
| 84 | and write it: |
| 85 | |
| 86 | # cat image > /sys/class/c2port/c2port0/flash_data |
| 87 | |
| 88 | after writing you have to reset the device to execute the new code: |
| 89 | |
| 90 | # echo 1 > /sys/class/c2port/c2port0/reset |